Expired probiotics: what is really in your cabinet?

Hannah Wilcox; Charles Carr; Shannon Seney; Gregor Reid; Jeremy P Burton

doi:10.1093/femsmc/xtaa007

Expired probiotics: what is really in your cabinet?

FEMS Microbes. 2020 Nov 6;1(1):xtaa007. doi: 10.1093/femsmc/xtaa007. eCollection 2020 Sep.

Authors

Hannah Wilcox^{1

2

3}, Charles Carr^{2

3}, Shannon Seney^{2

3}, Gregor Reid^{1

2

3}, Jeremy P Burton^{1

2

3

4}

Affiliations

¹ Department of Microbiology and Immunology, University of Western Ontario, 1151 Richmond St, London, ON N6A 3K7, Canada.
² Canadian Centre for Human Microbiome and Probiotics, LHRI, 268 Grosvenor St. London, ON, N6A 4V2 Canada.
³ Lawson Health Research Institute, 750 Base Line Rd E, London, ON N6C 2R5, Canada.
⁴ Division of Urology, Department of Surgery, Schulich School of Medicine, LHRI, 268 Grosvenor St. London, ON, N6A 4V2 CANADA.

Abstract

The popularity of using probiotics has surged, since they became widely accepted as safe and help improve general health. Inevitably, some of these products are used after expiration when microbial cell viability is below the recommended effective dose. Given that probiotics must be live microorganisms administered in adequate amounts, the aim of this study was to measure viability in expired products and assess how packaging and storage conditions impact efficacy, if at all. Thirty-three expired probiotic products were evaluated, of which 26 were stored in conditions recommended by the manufacturer. The viable microbial cells were enumerated and representative isolates identified by 16S and internally transcribed spacer rRNA gene sequencing. While the products had a mean past expiration time of 11.32 (1-22) years, 22 still had viable contents, and 5 were within or above the original product cell count claim. Product formulation and the number of species present did not appear to impact the stability of the products. However, overall packaging type, storage conditions and time since expiry were found to affect viability. All products with viable cells had the strain stipulated on the label. Despite some selected probiotic products retaining viability past their expiry date (indicating long-term storage is possible), the total counts were mostly well below that required for efficacious use as recommended by the manufacturer. Consuming expired probiotics may not yield the benefits for which they were designed.

Keywords: expired; health benefit; microbe; packaging; probiotic; storage.